This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Dr. Zhou's group is interested in the binding interaction of VRC05 antibody that recognizes glycans on HIV-1 gp120. The HIV-1 gp120-VRC05 complex was prepared by mixing glycosylated gp120 and VRC05 Fab, and then treated with EndoH to remove non-interacting glycans. The presence of VRC05 protected few glycans from EndoH digestion. Those glycans are critical for VRC05 binding to HIV-1 gp120. In this study, we took the part of investigating the site of glycosylation of this protein complex.